// https://leetcode.cn/problems/binary-tree-paths/

#include <vector>
#include <queue>
#include <sstream>
#include <iostream>
using namespace std;


struct TreeNode {
    int val;
    TreeNode *left;
    TreeNode *right;
    TreeNode() : val(0), left(nullptr), right(nullptr) {}
    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
    TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
};
class Solution {
public:
    vector<string> result;
    vector<string> binaryTreePaths(TreeNode* root) {
        backtrack("", root);
        return result;
    }

    void backtrack(string track, TreeNode* root){
        if(!root) return;
        //叶子节点
        if(root->left == nullptr && root->right == nullptr){
            track.append(std::to_string(root->val));
            result.push_back(track);
            return;
        }else{ // 非叶子节点
            track.append(std::to_string(root->val)).append("->");
            backtrack(track, root->left);

            backtrack(track, root->right);
        }
    }
};

void trimLeftTrailingSpaces(string &input) {
    input.erase(input.begin(), find_if(input.begin(), input.end(), [](int ch) {
        return !isspace(ch);
    }));
}

void trimRightTrailingSpaces(string &input) {
    input.erase(find_if(input.rbegin(), input.rend(), [](int ch) {
        return !isspace(ch);
    }).base(), input.end());
}

TreeNode* stringToTreeNode(string input) {
    trimLeftTrailingSpaces(input);
    trimRightTrailingSpaces(input);
    input = input.substr(1, input.length() - 2);
    if (!input.size()) {
        return nullptr;
    }

    string item;
    stringstream ss;
    ss.str(input);

    getline(ss, item, ',');
    TreeNode* root = new TreeNode(stoi(item));
    queue<TreeNode*> nodeQueue;
    nodeQueue.push(root);

    while (true) {
        TreeNode* node = nodeQueue.front();
        nodeQueue.pop();

        if (!getline(ss, item, ',')) {
            break;
        }

        trimLeftTrailingSpaces(item);
        if (item != "null") {
            int leftNumber = stoi(item);
            node->left = new TreeNode(leftNumber);
            nodeQueue.push(node->left);
        }

        if (!getline(ss, item, ',')) {
            break;
        }

        trimLeftTrailingSpaces(item);
        if (item != "null") {
            int rightNumber = stoi(item);
            node->right = new TreeNode(rightNumber);
            nodeQueue.push(node->right);
        }
    }
    return root;
}

int stringToInteger(string input) {
    return stoi(input);
}

string treeNodeToString(TreeNode* root) {
    if (root == nullptr) {
      return "[]";
    }

    string output = "";
    queue<TreeNode*> q;
    q.push(root);
    while(!q.empty()) {
        TreeNode* node = q.front();
        q.pop();

        if (node == nullptr) {
          output += "null, ";
          continue;
        }

        output += to_string(node->val) + ", ";
        q.push(node->left);
        q.push(node->right);
    }
    return "[" + output.substr(0, output.length() - 2) + "]";
}

int main() {
    string line;
    while (getline(cin, line)) {
        TreeNode* root = stringToTreeNode(line);
        Solution slu;
        vector<string> ret =  slu.binaryTreePaths(root);

        for(auto line : ret){
            for(auto ele : line){
                cout<<ele<<" ";
            }
            cout<<endl;
        }
    }
    return 0;
}